Kinetic energy can be solved by using the following formula: Kinetic energy = (1/2)*m*v^2
Where:
m = mass = 54 kg
v = velocity = 3 m/s
Since we are already given the needed values in the problem, direct substitution will be done:
KE = (1/2)*m*v^2
KE = (1/2) * 54 * (3)^2
KE = 243 J